Doctors use a system called STRAW+10 (Stages of Reproductive Aging Workshop +10 years) to divide the reproductive transition into clear stages. It was established by Harlow et al. (2012) and is the gold standard for staging reproductive aging.
How it works:
The stages are primarily defined by changes in the menstrual cycle. Here is a simplified summary:
Premenopause (-5): Regular, predictable cycles with no significant changes. Normal reproductive period.
Early perimenopause (-4 to -3): Cycles begin to vary by more than 7 days from your usual length. This shift indicates the start of the transition.
Late perimenopause (-2 to -1): Gaps of 60 or more days between periods. This is the most active transition period. This stage is strongly associated with increased VMS and sleep disruption.
Final Menstrual Stage (0): The milestone of 12 consecutive months without menstruation. It is confirmed retrospectively. The average age defined by the SWAN Study is 52.5 years.
Postmenopause (+1a, +1b, +1c): Years 1-10+, focus shifts to long-term cardiovascular, bone, and cognitive health.
From SWAN data: The bleeding patterns defined by STRAW+10 correlate well with symptom severity — sleep disturbance and VMS increase significantly in the -2 stage and peak around the FMP.